Researching Gerhard PRULL

Greetings,

I'm trying to gather information about my great-grandfather Gerhard PRULL,
b. 30 January 1848 in Oldenburg, Ostfriesland, Germany, d. 12 November
1902, Kanawha, Iowa, USA. I'm interested in knowing when and how he and
his wife (Marie Ahrenholtz) emigrated to the USA. Also I'm interested in
knowing who his ancenstors were in Germany.

I'd appreciate any help from anyone on this list who might have
information!

Thank you / Danke,

Matthew Prull